DESCRIPTION: The specific aims of this project are: to define cell survival and cellular perturbations as a function of drug concentration and duration of exposure, and to determine how the toxicity of these compounds is affected by the pH or cycling status of cells; to test the hypothesis that drug-induced perturbations produce radiopotentiation, and that irradiation of cells alters their drug response by delaying the cell cycle; to determine whether paclitaxel and docetaxel alter recovery from radiation-induced damage, and, to investigate the efficacy of combined treatment with paclitaxel or docetaxel and radiation in vivo.